Cirrus Logic CS42L73 - Manual (Page 113)

DS882F1 113
CS42L73
6.40 ALC Enable and Attack Rate AB (Address 2Fh)
6.40.1 ALC for Channels A and B (ALCx)
Enables ALC independently for channels A and B if ALC_AB = 0b (refer to “ALC Ganging of Channels A
and B” on page 116 ). If enabled, and if the particular channel’s signal amplitude exceeds the maximum
threshold setting or falls below the minimum threshold setting, ALC is applied to only that channel. If
ganged behavior is desired, set ALC_AB from 0b to 1b and then set ALCA and ALCB from 0b to 1b si-
multaneously.
6.40.2 ALC Attack Rate for Channels A and B
Sets the rate at which the ALC applies analog and/or digital attenuation from levels above the ALCMAX-
AB[2:0] threshold (
“ALC Maximum Threshold for Channels A and B” on page 114 ).
Note: The ALC attack rate is user selectable, but is also a function of the sampling frequency, Fs, the
PGASFT ( “PGA Soft-Ramp” on page 95 ), ANLGZC ( “Analog Zero Cross” on page 95 ), and DIGS-
FT ( “Digital Soft-Ramp” on page 96 ) settings unless either of the respective disable bits (ALCxS-
RDIS—refer to “ALCx Soft-Ramp Disable” on page 116 or ALCxZCDIS—refer to “ALCx Zero
Cross Disable” on page 116 ) is enabled.
6.41 ALC Release Rate AB (Address 30h)
6.41.1 ALC Release Rate for Channels A and B
Sets the rate at which the ALC releases the analog and/or digital attenuation from levels below the
ALCMINAB[2:0] threshold (
“ALC Minimum Threshold for Channels A and B” on page 114 ) and returns the
signal level to the PGAxVOL[5:0] ( “PGAx Volume” on page 98 ) and ADCxDVOL[7:0] ( “Input Path x Digital
Volume Control” on page 99 ) setting.
Notes:
• The ALC release rate is user selectable, but is also a function of the sampling frequency,
Fs, the PGASFT ( “PGA Soft-Ramp” on page 95 ), ANLGZC ( “Analog Zero Cross” on
page 95 ), and DIGSFT ( “Digital Soft-Ramp” on page 96 ) settings.
• The Release Rate setting must always be slower than the Attack Rate.
7 6 5 4 3 2 1 0
ALCB ALCA ALCARATEAB5 ALCARATEAB4 ALCARATEAB3 ALCARATEAB2 ALCARATEAB1 ALCARATEAB0
ALCx ALC Status
0 Disabled ALC on channel x
1 Enabled ALC on channel x
ALCARATEAB[5:0] Attack Time
00 0000
Fastest Attack
··· ···
11 1111 Slowest Attack
7 6 5 4 3 2 1 0
Reserved Reserved ALCRRATEAB5 ALCRRATEAB4 ALCRRATEAB3 ALCRRATEAB2 ALCRRATEAB1 ALCRRATEAB0
ALCRRATEAB[5:0] Release Time
00 0000
Fastest Release
··· ···
11 1111 Slowest Release